Every student of the twentieth century has heard both of the great Viennese economist Friedrich von Hayek and of the equally great philosopher Ludwig Wittgenstein. But what isn’t well known is that the two were distant cousins and that, shortly after Wittgenstein’s death in 1951, Hayek set out to write a biography of his cousin. The project was derailed by Wittgenstein family members, who felt it was to soon to publish such a work. But Hayek’s draft acquired an underground readership, and Wittgenstein’s biographers have used it extensively. Here finally, is the text of that work itself. Hayek’s account has the great merit of being close to its subject; the draft, moreover sheds light, not only on Wittgenstein but on Hayek as well. Allan Janik’s elegant afterword makes these links clear. Anyone interested in Wittgenstein or, for that matter, in the thought and culture of the earlier twentieth century, will want to read Christian Erbacher’s excellent edition of Hayek’s draft biography.